Need opinion on single speed 20" fat ebike gearing ratio : 40T front teeth / 12T rear teeth, would this be "inefficient"?

gembike223

New Member
i'm currently building a bike that is oriented towards mid-aged/late 40s/50s people (eg. my parents) who would like to get SOME exercise, go out but get some assist at maximum comfort. i currently am building a 20" 3in "fat" tire bike with full suspension (geared towards comfort on allterrain) but unfortunately it came with a very poor gear ratio.... 36t front 16t back, yielding 2.25 ratio which was way too high in cadence to get any real pedalling.
the bike has a 500w motor so it's powerful enough to get it "started", so i want to find ways to improve its pedalling cadence (actually allow me to use human power to get it going at high speeds). I thought about doing so by increasing the gear ratio, and relying on the motor to get it started from stop. My current options are to increase this to a 40t:12t = 3.33 or 38t:12t = 3.16, which one would be better..?

i'm fairly inspired by radrunner's single speeder as well, and the bike setup is quite similar. i know that they use 52t:16t = 3.25 . ratio is similar to what i want, but their cog sizes are larger and from what i read, that means it is more efficient. is MY setup above going to be a huge difference in terms of efficiency?
 
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